Datasheet

Pulse-Width Modulator (PWM)
M68HC12B Family Data Sheet, Rev. 9.1
134 Freescale Semiconductor
11.2.10 PWM Channel Period Registers 0–3
Read: Anytime
Write: Anytime
The value in the period register determines the period of the associated PWM channel. If written while the
channel is enabled, the new value takes effect when the existing period terminates, forcing the counter to
reset. The new period is then latched and is used until a new period value is written. Reading this register
returns the most recent value written. To start a new period immediately, write the new period value and
then write the counter, forcing a new period to start with the new period value.
Period = Channel-Clock-Period × (PWPER + 1)(CENTR = 0)
Period = Channel-Clock-Period × PWPER × 2(CENTR = 1)
Address: $004C
Bit 7654321Bit 0
Read:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset:11111111
Figure 11-16. PWM Channel Period Register 0 (PWPER0)
Address: $004D
Bit 7654321Bit 0
Read:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset:11111111
Figure 11-17. PWM Channel Period Register 1 (PWPER1)
Address: $004E
Bit 7654321Bit 0
Read:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset:11111111
Figure 11-18. PWM Channel Period Register 2 (PWPER2)
Address: $004F
Bit 7654321Bit 0
Read:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset:11111111
Figure 11-19. PWM Channel Period Register 3 (PWPER3)